On November 27th, 2013, Sojung was featured on a P-TYPE song with rapper San E, called Twisted.

Sojung was featured on two episodes of King of Mask Singer, on February 21st and 28th, 2016. Her identity wasn't revealed until the latter episode. Two of her songs from the show were officially released; Blue In You, a duet with Lee Taesung, and If You Come Back.

She was featured in a Jung Key song called I Don't Want, released on June 9th, 2016.

Starting in July, she competed in a JTBC singing competition called Idol Vocal League - Smells Like Girl Spirit, which features 11 other main vocalists of lesser-known Korean bands. She has released several studio versions of her songs from the show; Don't Be Shy, I Don't Love You, 24 Hours + NoNoNo, and One's Way Back. She advanced to the finals as the Wild Card, meaning she had the highest number of points aside from the top 4, but she didn't win the show.